1. Field of the Invention
The present invention relates to a mobile terminal device such as a cellular phone, a personal computer or an image forming apparatus, as well as to a method to manage the operation of such terminal device.
2. Description of the Related Art
Terminal devices such as cellular phones and personal computers known in the conventional art are equipped with a security function by which to prevent third parties from using such devices without the owner's permission.
For example, Japanese Laid-Open Patent Applications H11-184548, H9-167041 and H7-311715 disclose constructions that prohibit input or disable subsequent input when no operations or inputs are received for a certain period of time, and that cancel such input lock or disabled state when an appropriate password is input.
In addition, Japanese Laid-Open Patent Application H11-110209 discloses a construction that includes an expiration for the password such that unless the password is periodically re-registered, the terminal device cannot be used on a continuous basis.
Incidentally, a terminal device such as a cellular phone is often used by the owner during a business trip or while commuting, as well as at the regular place of use such as the office, for example, and when the terminal device is used during these occasions, the terminal device may be left on the train by the owner or stolen.
However, because the conventional technologies referred to above take into consideration only the security applicable at the regular place of use, they cannot effectively deal with issues that arise when the terminal device becomes separated from the owner against his will. For example, if a third party who finds the terminal device operates it without the owner's permission, confidential information and other personal information stored in the memory of the terminal device may be revealed via such operation.